My AAR isn't opening so when cold starting I have to keep the gas pedal depressed a bit. Has anyone had luck with cleaning this out (carb cleaner?) or rebuilding one?

rjkoop wrote:My AAR isn't opening so when cold starting I have to keep the gas pedal depressed a bit. Has anyone had luck with cleaning this out (carb cleaner?) or rebuilding one?

I have to research more before I ask questions sometimes. For the benefit of others...

http://www.hiperformancestore.com/Ljetronic.htm

And it explains how it works and what the electrical connector is for. I used carb cleaner to clean out the unit and I was able to get it cleaned out, understand the adjustment screw and I can see an opening when cold. So I think I'm good.

Spoke too soon. Even after cleaning the AAR a couple of times, ensuring the adjustment screw on the AAR maximizes the airflow through the unit, still doesn't bring the RPM up enough to keep the car running when cold. When I remove the AAR from the system (ie. use a straight through hose) it brings the RPM up to about 1400rpm which makes it idle fine when cold.

And after a bit more reading maybe it's just not getting the signal it needs from the ECU to open the valve.
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Auxiliary Air Regulator
Always a suspect when a FIAT is not idling properly, the Auxiliary Air
Regulator is an electrovalve that, when signaled by the ECU, allows
a metered amount of air to bypass the throttle plate and enter the
intake manifold. The obvious result is faster idle.
Failure of this device can cause the engine to idle too high or the
engine to run lean.
---
I thought I read somewhere that the connector was for another reason (heat the unit which I thought seemed weird) but obviously that was wrong. I'm going to check that connector!

So checked that the AAR was getting 12v when the engine was 1st turned on and it was.

So I decided to take the AAR apart. Pried the 2 sections apart and now I understand how it works. I'll try to post a few pictures for other who want to rebuild their AAR.

rjkoop wrote:

rjkoop wrote:My AAR isn't opening so when cold starting I have to keep the gas pedal depressed a bit. Has anyone had luck with cleaning this out (carb cleaner?) or rebuilding one?

I have to research more before I ask questions sometimes. For the benefit of others...

http://www.hiperformancestore.com/Ljetronic.htm

And it explains how it works and what the electrical connector is for. I used carb cleaner to clean out the unit and I was able to get it cleaned out, understand the adjustment screw and I can see an opening when cold. So I think I'm good.

What a GREAT link! A lot of wonderfully written information that an average shade tree mechanic can understand. A great read and I'm sure something I will come to use at some point... Thanks again for posting it up as I would never have found it on my own.

Got the connector and bimetallic strip out. There was a small pin/rivet holding the connector in (ie. the connector doesn't unscrew so don't break it trying). I measured the resistance between the 2 wire connectors and got about 46 ohms.





Started the engine (with the straight through hose in place of the AAR) and the wire in the AAR got warm and the strip started to bend. But after about 5 minutes this is all it did.



So I think this AAR is toast unless someone else has any ideas. Essentially the wire is getting hot but the bimetallic strip doesn't bend much at all. Do these things need to be cleaned?

Would the bending of the strip have rotated or slid the flap, closing down the opening and restricting the airflow after warm up?

What did the pieces of the flap and where it connected to the strip look like?

I am guessing here, but if the strip heated up and the bi-metallic strip has deflection, the problem is likely just mechanical at the orfice (i.e. In the flap mechanism)

76was124 wrote:Would the bending of the strip have rotated or slid the flap, closing down the opening and restricting the airflow after warm up?

What did the pieces of the flap and where it connected to the strip look like?

I am guessing here, but if the strip heated up and the bi-metallic strip has deflection, the problem is likely just mechanical at the orfice (i.e. In the flap mechanism)

Yep. The strip would swing to the left and rotate the flap to eventually close when warming up. For this to happen I think the strip needs about 3/8" of deflection at the end. I was only getting about 1/16" or so. The flap did have a broken piece which I'll try to JB weld but I still think I need more deflection from the bimetallic strip. I'm going to try a good cleaning.

I'm stubborn but I'm getting to the point where I'll just buy a used one.

rjkoop wrote: The flap did have a broken piece which I'll try to JB weld

I agree....a used one maybe easier, and would reduce the risk of JB weld or a bit of debris getting sucked in and scorching a cylinder!

This post is a little old, but he had two AARs, however he hasn't yet replied to my pm from a couple days ago.
http://fiatspider.com/f08/viewtopic.php?f=11&t=27022

The AAR does not open (and shut) much between hot and cold. They are a very simple, troublefree device.
Can you pinch off the hose to the AAR and will the car keep idling when engine warm?? It should.
Keith

majicwrench wrote:The AAR does not open (and shut) much between hot and cold. They are a very simple, troublefree device.
Can you pinch off the hose to the AAR and will the car keep idling when engine warm?? It should.
Keith

I've fought this AAR long enough. I've getting a used one from TwimCam for a great price. The flap on mine had broken a 2 locations so not worth the risk vs. spending the money on a used one.